I guess I have been misled by other's reports on their Mikuni's.

Folks here were reporting using them right out of the box with no changes. I've set the standard needles to their richest setting; I also have the chokes connected and working.

In desperation I even contacted the guy that sells Mikuni HSR kits for Triumph sportscars (since you-know-who doesn't answer emails), who lives about three hours south of me, and he stated that the carbs don't need seasonal adjustment (in his area?) and that the chokes and accelerator pump provide enough leeway under cold conditions.

I'd like to see a picture of the system that Volvo used for air heating; I had been thinking of constructing an air cleaner assembly that could pull air from inside the engine compartment or from behind the front grilles.

The only other thing I can think of would be yet another air leak in the induction system; although I have dismantled the entire induction system between the backs of the carbs and the ports on the head, and regasketed/resealed everything, which made a noticeable improvement in performance.

Could there be any issues with using a B18 crankcase ventilation setup on a B20 block?

Bill